observations from use 440C v S30C

[THEGRATENATE]

I do not have a lot of experience with different types of steels and knives, I was pretty happy with me BM model #350 and my BM Grip in 440C until now. I just recently got a well made knife in S30V with a BOS flame on it, I understand he does a really good job of heat treating.
The point of this post is that I had the 440C and S30V blades with me the other day with a whole lot of boxes to cut( in my opinion), I think I ended up taking the tops off of about fifty boxes that day. When I started I thought that the edge on the 440C was a little bit sharper than the S30V but I started to use the S30V just because it's a nicer overall knife(Graham Bros Razel incase anyone is curios). After a bit of work I thought the S30V was starting to get dull, so I brought out the 440C and used it for a few minutes. The interesting thing is that it only took a few minutes before I found myself pulling with both hands to get the 440C through cardboard and folded it back up in favor of the S30V, which then went the rest of the day without seeming to dull anymore at all( I did begin to pay better attention the the angle I was useing to cut, that 3/16" spine binds up real easy).

This is a question not a statement so now I will ask the question.
Are my results typical of the differences between "common" steels and higher end steels? OR did the edge that these blades have on them skew my results. I am by no means discussing a scientific process here, but I would like some unbiased or maybe even scientific information now that I have my "seatofthepants" observations to go by. My experience was that the S30V lasted literally 4 times as long as the 440C, but as I said this was not scientific and by no means constitutes "research".

So is there anyone out there with who has actually researched this or who has more expirience with edges that would be called similar?
Thanks

 

[HoB]

Your experience is really not surprising. S30V when treated right IS a very wear resistant steel. Also you used it in an activity where the wear resistance truly shines: Cardboard is a very abrasive material. Finally, since you were using normal factory geometries, you were likely in a regime were edge stability due to high carbide volume is not much of a problem yet....not that 440C would fair any better, the carbide volume is lower but the grain and carbide structure should be MUCH larger than that of well treated S30V.

So, bottom line, you just performed one of those tests where S30V is really able to outshine most other common bladesteels.

 

[gabsliceoflife]

S30V has more wear resistance and would most likely do better all things being equal, but they usually are not. There are other things that affect that. One is tempering rockwell hardness has some to do with it. A blade that is 56-58 is not as ware resistant as one that is 58-60. But it also will be more brittle. You should if you want peak preformance. That is why there is no one knife for every task. You should also look at blade geomtery ie. how thin is the cutting edge.
I have done some cutting tests not scientific by any means, but I cut different things and found that 440c was very good when tempered right. But ATS34 or 154cm out preformed it. Now this was a while ago I have not preformed this with S30v but would expect it to do well from using it.
I have noticed a other question about sharping I have heard that if you let S30v get dull then it is very hard to resharpen. So if you know how to sharpen then it might be better to have one you can sharpen, or make sure you never let it get dull.

 

[sog]

What is the angle of the edge on both knives? A more acute angle might skew the results.

 

[STR]

I'm not surprised. The wear resistance of the S30V blade will be much better than 440C and as a result the edge just simply lasts longer. The only thing better would be another S30V blade fully serrated. These quite literally cut cardboard for a very very long time before seeing significant changes to the cutting performance. My Dodo ripped apart close to 50 boxes when we cleaned up the shed and threw out a bunch of stuff and its still ready for a couple hundred more.

STR

 

[Cliff Stamp]

OR did the edge that these blades have on them skew my results.

Pretty much all aspects of blade effect the results, most critical is the grit used to finish and the angle of the edge. But the curvature of the blade also can have an influence as will the handle as both effect how the edge is presented to the wood. However as the others posters noted, you would expect S30V to have an advatnage over 440C, though based on the amount you saw I would suspect there was a significant difference in initial edge angle and/or sharpness as well.

-Cliff

 

[hardheart]

Well, this morning I made 100 cuts in cardboard with 5 knives - Benchmade M2 and D2, Byrd 8Cr13MoV, custom CPM154, and Spyderco S30V. All were given a microbevel with Spyderco fine ceramic and then stropped on chromium oxide loaded leather. the D2, S30V, and CPM154 received 20 degree per side, the M2 15 per, and the Byrd has a chisel edge polished freehand.

After the 100 cuts each, the S30V had chipped in half a dozen places, while the CPM154 and M2 had one each along the length of the blade. It was difficult to tell with the D2, as the edge was irregular before the cutting, but it did not experience any chipping comparable to the level of the S30V. The Byrd did not chip, but it is around .010" thicker behind the edge than the others, and was the hardest to cut with despite the clean shaving edge. The model 46 Benchmade was almost as difficult to use, both requiring more force than the others and making me space my strips out further. I began the cutting a few days ago with just the S30V to see how it held up, and I found I could get 40 cuts per side of a cardboard tray without trouble. With the Byrd and 46, I was barely getting 35, and I got nearly 50 per side with the M2.

Handle ergos, blade geometry, heat treat, and steel all have an effect.

btw, I think I can get pics of these chips, I can focus my camera through my magnifier, just need a stable base for it.

 

[THEGRATENATE]

Pretty much all aspects of blade effect the results, most critical is the grit used to finish and the angle of the edge. But the curvature of the blade also can have an influence as will the handle as both effect how the edge is presented to the wood. However as the others posters noted, you would expect S30V to have an advatnage over 440C, though based on the amount you saw I would suspect there was a significant difference in initial edge angle and/or sharpness as well.

-Cliff

If I use a mouse pad and sandpaper to sharpen, at what grit will I start to get really good results? Also will this vary based on the steel that I am sharpening?
The S30V is a Razel that has not been resharpened since it came from Graham Brothers, I am the second owner and I was told that the first owner had "dulled" the blade cutting boxes. I don't know how they sharpen their knives, but it does appear to have a micro-bevel on it and looks like it was polished, there sure as heck ain't no grinder marks on this thing.
The 440C is a Benchmade that I had "tried" to sharpen with sandpaper and a mousepad, I have up to 440 grit, and I think I did get it about as sharp, if not a little bit sharper than it came from the factory.
Thanks
Nate

 

[hardheart]

hmm, you really should have seen a noticeable difference between 400 finish 440C and polished S30V, so no surprises. which BM did you use, the 350 or the griptilian. And which grip do you have, the clip point or sheepsfoot?

 

[THEGRATENATE]

The BM is the modified sheepsfoot in 440C, and I don't recall the steel that is used for the 350, I'm sure it was a big deal almost a decade ago when I ordered it, but today it's just an old friend, that was at home on the day in question.
It seems odd to me that an Arkansas stone will get a knife "sharp" with a grit that appears twice as coarse as the 400 paper. Maybe that's part of the reason my mousepad seems so much easier to use.
So what numbers in paper do I need to use before it is considered polished?

 

[hardheart]

here's a page I use to look up grit sizes for different materials. You'll note that 400 silicon carbide is not that fine a grit in comparison, but you can still get a sharp edge, it's just toothier.

http://users.ameritech.net/knives/grits.htm

my 530, which is essentially an axis version of the 350, was 440C, I had thought maybe they used the same steel. Might be ATS34 or 154CM. BMs are usually marked with the steel, maybe double check the blade by the thumbstud on the linerlock side?

 

[THEGRATENATE]

Thanks for the link,
I double checked, and I can't find any markings alluding to steel, I a recall that I bought the 350 when ats34 was some pretty good stuff, I think I had seen a mention of D2 at the time but it was way out of my price range, so I'll go with ats34 as an edumecaded guestimate. The 530 replaced the 350 in the lineup when I wasn't looking, like anytime between the time I bought mine and last week. IIRC we were united sometime in '98 or '99, this thing really is like an old friend to me.

 

[Cliff Stamp]

The 440C is a Benchmade that I had "tried" to sharpen with sandpaper and a mousepad, I have up to 440 grit, and I think I did get it about as sharp, if not a little bit sharper than it came from the factory.

As hardheart noted, the large grit difference was likely as significant as the steels. If you are just pushing the blade through the cardboard, meaning no drawing the blade from choil to tip, then you want a really high polish, this means grit of paper in the thousands.

After the 100 cuts each, the S30V had chipped in half a dozen places, while the CPM154 and M2 had one each along the length of the blade.

Same general size/structure?

It was difficult to tell with the D2, as the edge was irregular before the cutting, but it did not experience any chipping comparable to the level of the S30V.

These are fairly large angles? How irregular was the edge on the D2 initially compared to the chips which later formed in the others.

The Byrd did not chip, but it is around .010" thicker behind the edge than the others, and was the hardest to cut with despite the clean shaving edge. The model 46 Benchmade was almost as difficult to use, both requiring more force than the others and making me space my strips out further.

Assuming the chips are very small and not actually exceeding the width of the edge, a thicker edge tends to be more prone to chips because the reduction in cutting ability increases stresses in a given cut.

I began the cutting a few days ago with just the S30V to see how it held up, and I found I could get 40 cuts per side of a cardboard tray without trouble. With the Byrd and 46, I was barely getting 35, and I got nearly 50 per side with the M2.

So the S30V blade can still make more cuts than the Byrd even though there is less visible damage.

-Cliff

 

[hardheart]

Same general size/structure?

No. I put up a few pics in the micrograph thread, but couldn't get the one of the M2 chip. It didn't look anything like the S30V chips, it was just an irregular portion of the edge, which was otherwise very straight. same for the CPM154, which was so small I couldn't get a shot of it.

These are fairly large angles? How irregular was the edge on the D2 initially compared to the chips which later formed in the others.

You can see it somewhat in the picture, the edge is just sort of wavy. It also doesn't polish up much at all, but it's D2.

Assuming the chips are very small and not actually exceeding the width of the edge, a thicker edge tends to be more prone to chips because the reduction in cutting ability increases stresses in a given cut.

Well, I didn't put a micro on the Cara, just went over the edge bevel a few passes with the fine ceramic and strop to try and get the edge finish the same as the other knives. It's a combo edge, like the one you tested. I'm not sure if a change needs to be made in the estimating of the angle, since it's hollow ground on both sides but just sharpened on one. It's 0.036" thick behind the edge and the bevel is 0.090" wide.

So the S30V blade can still make more cuts than the Byrd even though there is less visible damage.

Yes, but it's geometry and not so much steel for what I did. I had to space the cuts out more from the very beginning because it was harder to cut with the Cara.